> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/taskforcesh/bullmq/llms.txt
> Use this file to discover all available pages before exploring further.

# AWS ElastiCache

> Configure AWS ElastiCache for Redis to work with BullMQ

ElastiCache is a managed caching service offered by Amazon Web Services (AWS), and it can be a good option when using BullMQ within the AWS infrastructure.

## Important Requirements

<Warning>
  **Critical Configuration Requirements:**

  * Use the **standard cache-nodes setup** (not serverless)
  * Set `maxmemory-policy` to **`noeviction`**
  * Configure proper **security groups** for network access
</Warning>

<Info>
  The serverless version of ElastiCache currently uses an incompatible maxmemory-policy and cannot be used with BullMQ.
</Info>

## Setup Guide

<Steps>
  <Step title="Create a Security Group">
    Create a security group that allows your BullMQ services to access ElastiCache.

    1. Go to EC2 > Security Groups
    2. Click "Create Security Group"
    3. Add an **Inbound rule**:
       * Type: Custom TCP
       * Port range: 6379
       * Source: Choose based on your needs (for testing, "Anywhere" works, but use specific security groups in production)

    <Note>
      The cluster will not be accessible outside AWS regardless of the security group configuration.
    </Note>
  </Step>

  <Step title="Create a Custom Parameter Group">
    You need to create a custom parameter group to set the correct `maxmemory-policy`.

    1. Go to **ElastiCache > Parameter Groups**
    2. Click **"Create"**
    3. Fill in:
       * **Name**: e.g., `bullmq-params`
       * **Description**: e.g., `Parameters for BullMQ`
       * **Family**: `redis7` (or latest available)
    4. Click **"Create"**
  </Step>

  <Step title="Configure maxmemory-policy">
    Update the parameter group to use `noeviction` policy.

    1. Find your parameter group in the list
    2. Click **"Edit parameter values"**
    3. Search for **`maxmemory-policy`**
    4. Change the value to **`noeviction`**
    5. Click **"Save changes"**

    <Warning>
      This is critical! BullMQ cannot work properly if Redis evicts keys arbitrarily. The `noeviction` policy ensures Redis will refuse write operations instead of removing keys when memory is full.
    </Warning>
  </Step>

  <Step title="Create or Modify ElastiCache Cluster">
    Create a new cluster or modify an existing one to use your custom parameter group.

    **For new clusters:**

    1. Go to **ElastiCache > Redis clusters**
    2. Click **"Create"**
    3. Choose **standard cache** (not serverless)
    4. Select your **custom parameter group**
    5. Attach your **security group**

    **For existing clusters:**

    1. Find your cluster
    2. Click **"Modify"**
    3. Go to **Cluster settings**
    4. Change the **Parameter group** to your custom group
    5. Preview changes and **"Modify"**
  </Step>

  <Step title="Attach Security Group">
    Attach the security group to:

    * Your ElastiCache cluster
    * The EC2 instances or services that need to access it
  </Step>
</Steps>

## Connection Example

Once your ElastiCache cluster is configured, connect to it using BullMQ:

```typescript theme={null}
import { Queue, Worker } from 'bullmq';

const connection = {
  host: 'your-elasticache-endpoint.cache.amazonaws.com',
  port: 6379,
};

// Create queue
const queue = new Queue('myqueue', { connection });

// Create worker
const worker = new Worker(
  'myqueue',
  async (job) => {
    console.log('Processing job:', job.id);
    // Process your job
  },
  { connection }
);
```

## Verification Checklist

Before using ElastiCache in production, verify:

<AccordionGroup>
  <Accordion title="Security Configuration">
    * [ ] Security group allows inbound connections on port 6379
    * [ ] Security group is attached to ElastiCache cluster
    * [ ] Security group is attached to your application instances
  </Accordion>

  <Accordion title="Parameter Configuration">
    * [ ] Created custom parameter group
    * [ ] Set `maxmemory-policy` to `noeviction`
    * [ ] Applied parameter group to cluster
  </Accordion>

  <Accordion title="Cluster Configuration">
    * [ ] Using standard cache (not serverless)
    * [ ] Redis version 6.2.0 or newer
    * [ ] Cluster is in the correct VPC
  </Accordion>
</AccordionGroup>

## Cluster Mode vs Standard Mode

<Tabs>
  <Tab title="Standard Mode (Recommended for Simplicity)">
    Use standard mode for simpler setups:

    ```typescript theme={null}
    import { Queue, Worker } from 'bullmq';

    const connection = {
      host: 'your-cluster.cache.amazonaws.com',
      port: 6379,
    };

    const queue = new Queue('myqueue', { connection });
    ```
  </Tab>

  <Tab title="Cluster Mode (For High Availability)">
    If using cluster mode, use IORedis Cluster:

    ```typescript theme={null}
    import { Cluster } from 'ioredis';
    import { Queue, Worker } from 'bullmq';

    const connection = new Cluster([
      {
        host: 'your-cluster.cache.amazonaws.com',
        port: 6379,
      },
    ]);

    // Use hash tags in queue names
    const queue = new Queue('{myqueue}', { connection });
    ```
  </Tab>
</Tabs>

## Related Resources

<CardGroup cols={2}>
  <Card title="AWS MemoryDB" icon="database" href="/redis/hosting-aws-memorydb">
    Alternative AWS managed Redis option with different features
  </Card>

  <Card title="Going to Production" icon="rocket" href="/operations/going-to-production">
    Production deployment best practices
  </Card>
</CardGroup>